K2-141 b: A 5- M super-Earth transiting a K7 v star every 6.7 h

O. Barragán, D. Gandolfi, F. Dai, J. Livingston, C. M. Persson, T. Hirano, N. Narita, Sz Csizmadia, J. N. Winn, D. Nespral, J. Prieto-Arranz, A. M.S. Smith, G. Nowak, S. Albrecht, G. Antoniciello, A. Bo Justesen, J. Cabrera, W. D. Cochran, H. Deeg, Ph EigmullerM. Endl, A. Erikson, M. Fridlund, A. Fukui, S. Grziwa, E. Guenther, A. P. Hatzes, D. Hidalgo, M. C. Johnson, J. Korth, E. Palle, M. Patzold, H. Rauer, Y. Tanaka, V. Van Eylen

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


We report on the discovery of K2-141 b (EPIC 246393474 b), an ultra-short-period super-Earth on a 6.7 h orbit transiting an active K7 V star based on data from K2 campaign 12. We confirmed the planet's existence and measured its mass with a series of follow-up observations: seeing-limited Muscat imaging, NESSI high-resolution speckle observations, and FIES and HARPS high-precision radial-velocity monitoring. K2-141 b has a mass of 5.31 ± 0.46 M and radius of 1.54-0.09+0.10 R, yielding a mean density of 8.00-1.45+1.83 g cm-3 and suggesting a rocky-iron composition. Models indicate that iron cannot exceed ∼70% of the total mass. With an orbital period of only 6.7 h, K2-141 b is the shortest-period planet known to date with a precisely determined mass.

Original languageEnglish (US)
Article numberA95
JournalAstronomy and Astrophysics
StatePublished - Apr 1 2018

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Planetary systems
  • Planets and satellites: individual: EPIC 246393474 b
  • Stars: fundamental parameters
  • Stars: individual: EPIC 246393474
  • Techniques: photometric
  • Techniques: radial velocities


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